The present invention relates to an abnormality detection method for a power circuit which is contained in a vehicle motor control unit.
Traditionally, relays are generally used to control a power supply from a high-voltage battery to an electric motor or the like. For example, in electrically driven vehicles such as hybrid vehicles or electric vehicles, in order to control a power supply from a high-voltage battery to an inverter which is a load circuit, a power source relay is provided between the battery and the inverter, so that closing and opening a circuit between the battery and the inverter are carried out according to the controlled state of the vehicle by the power source relay. As this occurs, a large rush current flows momentarily from the battery to charge a smoothing condenser of a large capacity, leading to a situation in which contacts of the power source relay are fused. To prevent a risk of failing to cut off the flow of current by switching off the power source relay due to the fused contacts which are kept in contact with each other, a power circuit is proposed which includes a pre-charge circuit which is configured to pre-charge the smoothing condenser before the power relay is switched on (for example, refer to Patent Document 1).
[Patent Document 1] JP-A-2001-128305